This disclosure relates generally to noise reduction or cancellation and more specifically to pre-configuring and controlling a noise cancellation circuit.
Noise cancellation systems are becoming increasingly important and vital to the proper functioning of various devices such as cell phones, personal digital assistants (PDAs), Global Positioning System (GPS) systems; computer systems, video game consoles, and so on. As devices become smaller and include multiple sources of noise such as Bluetooth, 802.11x, GPS or other digital or analog transceivers; display screens, clocks, power switching, etc., the ability to provide fast and effective noise cancellation can become vital. Today's applications often demand power-efficient noise canceling systems that can quickly reduce or eliminate undesirable signals, such as Radio Frequency (RF) noise and interference, in accompanying system components.
Effective noise canceling systems are particularly important in wireless applications, such as cellular telephones, where radio interference may cause dropped calls, loss of data, or other non-performance effects. A noise canceling system may measure noise in a signal environment and then output a signal designed to cancel the noise. The faster that the noise cancellation subsystem can converge on the noise signal (i.e., generate a matching signal to cancel the noise signal) the more effective is the noise cancellation. Also, power consumption is always an important aspect of circuitry in a portable device, so it is desirable to make the generation and application of the noise cancellation signal as power-efficient as possible.